Windows Vista system comes awake by itself after shutdown

I'm running Vista Home Premium and have been for over two years now. I've a Toshiba P200 laptop.

When I close the lid on this rig, it goes to sleep. The last couple nights, I've noticed when I get up, the computer is out of sleep and running. Last night was the same, so I came in and lifted the lid and closed it again. It went to sleep.

This morning when I got up, the thing was out of sleep and running again. Any ideas why this is doing this and how I can get it to remain asleep other than giving it a sleeping pill?

 

Everything is on (Checking e-mail / Norton 360 plus everything else) but then again, it always has been. When the lid has been shut down, nothing starts it unless Vista does an update. But I've not seen anything to indicate such, unless it did a sneak attack.

Today, I've left the lid down all day and it didn't come out of sleep, so it might have been just an update or a fluke.

I've got the Fire Extinguisher close by just perchance .................